Microphones convert sounds to electrical signals and are used with a variety of devices where voice communication is desired. Microphones may be used in or with portable two-way radios. For example, a microphone in a portable two-way radio (a first portable two-way radio) generates a speech signal which may be encoded by the portable two-way radio and then transmitted to another or second portable two-way radio. The second portable two-way radio receives the encoded signal and then decodes that signal. Likewise, the second portable two-way radio encodes and transmits speech signals to be received and decoded by the first portable two-way radio. When a speech signal of poor speech quality is encoded at the first portable two-way radio, the decoded speech output at the second portable two-way radio can be unintelligible. A poor speech signal can be caused by, among other things, wind-induced noise in the microphone.
Each of the portable two-way radios processes the decoded signal to produce sound from a speaker in the portable two-way radio, or from a speaker in a remote speaker microphone (“RSM”) accessory attached to the portable two-way radio. In portable two-way radios and remote speaker microphones, the speaker is located beneath a speaker grille in the device. Users of portable two-way radios will often direct their speech responses to the source of the speech to which they are responding by speaking into the speaker grille. Accordingly, the microphone for the portable two-way radio is often located near the speaker grille, for example, in a cavity beneath the speaker grille. Sound waves from the user's speech reach the microphone through an opening located above the microphone, known as a microphone port. Wind-induced noise can be caused when a microphone with a conventional microphone port is used in windy conditions, and the wind passing over the surface of the microphone port causes the formation of discrete vortices in the vicinity of the microphone port. These vortices lead to turbulence, which creates noise. This wind-induced noise degrades the speech signal being picked up by the microphone, which ultimately degrades the intelligibility of the speech produced when the speech signal is decoded by the receiving portable two-way radio.
Microphone ports designed to reduce wind-induced noise, i.e., wind ports, are known, in general. Known wind ports include, for example, a recessed-opening microphone port, a tortuous path microphone port, and a big-front volume microphone port. Each of these known ports includes a microphone mounted in a housing, with a microphone port or ports to allow sound to reach the microphone. A conventional, recessed-opening microphone port includes a single opening recessed in the housing for the microphone. A tortuous path microphone port includes a microphone mounted near the edge of a speaker located beneath the housing, and a small path located near the edge of the speaker, connecting the microphone and the speaker grille area. Sound travels to the speaker grille, and then through the path to the microphone. A big-front volume microphone port includes one or more openings in the housing, positioned above a space that provides for a large (relative to the microphone) volume of air above the microphone. Some of these known wind port designs may create an uneven frequency response in the microphone over the voice band, and others require a large amount of space to implement.
Accordingly, there is a need for a slim-tunnel wind port for a communication device.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.
The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.